1. Field of the Invention
This invention generally relates to a backlight module of a liquid crystal display, and more particularly to a backlight module which is easily assembled and has a good property for heat dissipating.
2. Description of the Related Art
Due to the advance of electronic technology, especially for the popularity of portable electronic products, the requirements of light, compact and low-energy consuming display are gradually increasing. With the advantages of low-energy consuming, low-heat dissipation, light weight and non-luminescence, liquid crystal displays (LCD) have been widely used in the electronic products and even have replaced the traditional CRT displays.
Referring to FIG. 1, it depicts the structure of a liquid crystal display in the prior art. In general, a liquid crystal display device includes a liquid crystal panel 10, and the liquid crystal panel 10 includes two substrates and a liquid crystal disposed therebetween. A backlight module is disposed under the liquid crystal panel 10 for distributing the light from a light source uniformly over the surface of the liquid crystal panel 10. These backlight modules typically include two types, i.e. a direct back light type and an edge light type. Furthermore, the liquid crystal display device typically further includes a front frame 11.
The prior art references have provided many backlight modules, e.g., U.S. Pat. No. 6,407,781 B2, issued Jun. 18, 2002 to Titada and U.S. Pat. No. 6,417,833 B1, issued Jul. 9, 2002 to Takemoto et al., which are both incorporated herein by reference.
Referring to FIG. 2, it shows a cross-sectional view of a direct back light type backlight module 21 taken along line 2-2 in FIG. 1. The direct back light type backlight module 21 includes a housing 70, a reflecting sheet 60 disposed at the base of the housing 70, lamps 50, such as cold cathode fluorescent lamps (CCFL), disposed at the base of the housing 70, a diffuser 40 disposed on the housing 70, and a plurality of optical sheets, such as a prism sheet 30 and a diffusing sheet 35, disposed on the diffuser 40.
The lamps 50 are spaced each other and disposed on a display area of the liquid crystal panel 10; therefore, the illumination distribution of the liquid crystal panel is not uniform. Typically, it is required to keep a predetermined distance or space between the lamps 50 and the diffuser 40. A spacer 55 of the housing 20 generally provides the predetermined distance or space.
Typically, the lamps 50 are mounted on a side wall of the housing 70 by a lamp fixture or a lamp support member (which is generally called). The lamp support member is quite rigid, and therefore a lamp rubber, which is made of silicon rubber for example, is disposed between the lamp support member and the lamp for acting as a damper. However, the housing 70, the lamp support member and the lamp rubber are respectively made of different materials, and are assembled in sequence, such that the assembling process need much time and manpower. Furthermore, the lamp support member and the lamp rubber are made of insulated material, and it is difficult to conduct the heat generated from the lamp, thereby resulting in the deformation of optical elements, e.g. the diffuser 40, the prism sheet 30 and the diffusing sheet 35, and further affecting the image quality of the LCD.
Referring to FIG. 3, it shows a cross-sectional view of an edge light type backlight module 21 taken along line 2-2 in FIG. 1. The edge light type backlight module 22 includes a light guide 80, lamps 50 disposed at one or two sides of the light guide 80 and an U-shaped reflector 61 enclosing the lamp 50. An opening portion of the reflector 61 is mounted at the side of the light guide 80, a reflecting sheet 60 is mounted at the bottom of the light guide 80, a diffusing sheet 35 is mounted over the light guide 80, and a prism sheet 30 is mounted over the diffusing sheet 35. The lamp 50 is disposed at the edge of the light guide 80, and the thickness of the LCD can be decreased. Similarly, according to the edge light type backlight module 22, the heat generated from the lamp 50 may also cause the deformation of the diffusing sheet 35 or the light guide 80, and further affect the image quality of the LCD.
Accordingly, there is a need for providing a liquid crystal display which has a simple structure, is easily assembled and dissipating the heat generated from a lamp.